Radiofrequency transformer



1 6231 43 Aprll 5, 1927. R M WARREN RADIOFREQUENCY TRANSFORMER Filed Jan. 9, 1924 INVENTOR ROBERT M. WARR EN.

' ATTORNEY Patented Apr. 5, 1927.

UNITED STATES 1, 23,143 PATENT OFFICE.

ROBERT M. WARREN, OF EAST ORANGE, NEW JERSEY, ASSIGNOR T DUBILIER CON- DENSER CORPORATION, A CORPORATION OF DELAWARE.

RADIOFREQUENCY TRANSFORMER.

Application filed January 9, 1924. Serial No. 685,241.

This invention relates to an improvement in electrical transformers, especially spacing and retaining means for the magnetic cores of transformers for usein radio apparatus An object of the invention is to provide a transformer core in sections, the extremities of which are spaced apart to leave an air gap between them, with suitable means, acting without requiring the boring of holes in the transformer or the use of screws, or other special working of any part of the core, to engage the sections and hold them in fixed position so as to prevent the extremities of the sections being moved closer together or farther apart, and thereby maintain the di mensions of the air 'gap constant.

The manner in which my invention is practiced is set forth in the following description, together with the accompanying drawings, upon'which an embodiment of my invention is illustrated; and I of course reserve the right to adopt variations ofstructure which do not depart from the principle of the invention, as the same is broadly defined in the appended claims.

On the drawings Figure 1 is a side view of a transformer according to my invention.

Figure 2 is an end View of same.

Figure 3 is a'bottom view.

Figure 4 is a plan view of a retaining element for the sections of which the core is composed.

Figure 5 is a plan view of a spacing element for the core. 1

Figures 6 and 7 are views of the sections of which the core is made up, in the relative positions given to such sections when the core is about to be assembled.

Figure 8 shows how the retaining element and the spacing element co-operate to secure the two sections of the core together in fixed position with their extremities a c0nstant distance apart.

The same numerals identify the same parts throughout. I

Referring first to Fig. 1, I show the core of a transformer comprising two L-shaped v sections A and 13, arranged so as to make a continuous magnetic circuit of rectangular configuration in this instance, but with the extremities of the sections separated to provide air gaps G. Inradio work, particularly with oscillations at radio frequency, the presence of such air gaps in the magnetic known to those skilled in this art and need not be stated here other than merely by way of reference. It is the main purpose of my invention to enable the sections A and B to be held together in fixed relation and prevented from moving either closer together or away from one another, so as to keep the air gaps G of constant width; for such air gaps must be carefully designed, and it is very important to keep such air gaps from changing and becoming longer or shorter when the transformer is in service.

As already mentioned, the two sections A and B are preferably L-shaped, each having a stem 1 and a base 2. But since one of the sections, for example, the section A at the right of Fig. l, is inverted with respect to the section when the two sections of the transformer core are in position to be assembled, I shall designate the portions 2 as laterally extending portions, instead of bases. On the stem of the section A may be placed a coil 8, and on the stem of the other section B is a coil 4', these coils bein extended to have a mutually inductive e ect upon each other in a well-known manner.

To join the two sections in a magnetic circuit having gaps G of the fixed size required, I employ a retaining elementin the form of a loop or link 5 and a spacing element 6. The link 5 may be rectangular or oblong in shape, with inside and outside corners conforming to the shape of the sectionsA and B, while the element 6 is H-shaped with parallel projections or fingers 7 at each end, separated by recesses 8, and having a transverse central portion 9. 1 The two elements are combined in the manner shown in Fig. 8, the element 5 being laid upon the top of the element 6, so that the sides of the element 5 coincide with two aligned fingers 7 at one side of the element 6, and the other side of the link '5 will coincide with the two remaining fingers 7. Also, the extremities of the link 5 will bridge the extremities of the parallel fingers 7 and thusconvert the recesses 8 into closed apertures 8 of the same size and shape as the cross section of the stems 1 of the sections A and B. Hence, if a spacing element 5 and a retaining element 6 be employed at each end of the transformer core, the two extremities of each section will be held securely together and kept apart a fixed distance.

The manner in which the spacing and retaining means comprising the link 5 and element 6 is utilized will now be obvious. One simply puts the two sections A and B in the relative positions shown in Figs. 1, 6 and 7, and places a retaining element 6 against the inner faces of the lateral portions 2; that is to say, one element 6 will be directly beneath the portion 2 of the section A, and the other element will be directly upon the portion 2 of sections B, the stems 1 of the two sections fitting into the opposite recesses 8, and each stem being engaged near its upper and lower part at the sides by the fingers 7 at the sidesof these recesses. Of course, the coils 3 and 4 are disposed upon sections A and B beforehand. After the elements 6 are properly placed'between the sections, the loops 5 are slipped over the opposite ends of the transformer core, so that one loop 5 encircles the upper end of the stem 1 of the section B, and the stem 1 of the section A at the point of its junction with the portion 2; and, the other loop 5 encircles the lower end of the stem 1 of the section A, and goes around the section B at the lower part adjacent the laterally extending portion 2 thereof. The elements 5 and 6 will of course need to fit the sections A and B snugly, and thus the sections will be held tight by the elements 5 and 6 at the top and bottom of the transformer core, the elements 5 preventing them from separating, and the elements 6 keeping them from moving any closer together. Hence the distance across the air gaps G never varies.

It will now be apparent that I have devised an exceedingly simple and effective means for achieving the objects of this invention. When the sections are made up in the form required, they require no boring of holes as would be the case if screws or pins were employed, or any working of any kind to make them ready to have the spacing and retaining means attached. The sections A and B are of course laminated, while the elements 5 and 6 can be easily manufactured and made of any suitable material.

I do not wish to be necessarily limited in practice to the use of sections which are L-shaped, or square in cross section, as I may utilize my spacing and retaining ,means for sections having a different form. and still keep within the spirit and scope of my invention.

Having described my invention, what I believe to be new and desire to secure and protect by Letters Patent of the United States is 1. A magnetic core comprising a pair of sections, the extremities of which are spaced apart to provide an air gap, a spacing element to hold the extremities a fixed distance apart, and a. retaining element co-operating with the spacing element to prevent the air gap being increased.

2. A magnetic core comprising a pair of sections, the extremities of one being spaced from the extremities of the other, to provide air gaps, a spacing element adjacent each gap to hold the extremities a fixed distance apart, and a retaining element co-operating with each spacing element to prevent the air gap being increased.

3. A magnetic core comprising a pair of sections the extremities of which are spaced apart to provide an air gap, a spacing element disposed between said sections and engaging same at its opposite ends to prevent the extremities of said sections from being moved closer together, and a retaining element encircling the sections to prevent the extremities from being moved apart.

In testimony whereof I afiix my signature.

ROBERT M. WARREN. 

